The government will take stern measures against people who spread "groundless rumors" about the sunken frigate Cheonan through Internet portals and other mediums.

Maeng Hyung-kyu, minister of public administration and security, held an emergency meeting following the military's announcement on the cause of the Cheonan sinking Thursday and ordered a crackdown on rumors being spread through cyberspace.

Maeng has also ordered officials to keep a tight rein on any illegal gatherings regarding the Cheonan tragedy.

This is not the first time the administration has planned to punish online rumormongers. The prosecution indicted a 22-year-old Internet user last week for faking his identification as a military insider claiming that military authorities have ignored the possible danger the frigate was in before it sank.

The man identified as Jang posted articles on major portal sites that he saw the military officials not paying attention to reports from Cheonan because they were on a "training" session with the U.S. military. He introduced himself as Lieutenant Commander Kim.

However, the man he made himself out to be was in fact not close to the authorities, and they sued him for libel and other charges. Jang has reportedly deleted his article but Kim and the prosecution has decided to take action to set an example.

"Anyone who makes false reports or articles about the incident could seriously damage national security. We will not let these be the basis of any risks the nation faces," the prosecution said earlier.

The ministry has decided to alert its staff to secure food, oil and other necessities in case of emergency. An extra alert was issued to guards at public administrative buildings and online information management systems against possible cyber attacks. Public officials were asked not to drink alcohol or enjoy nighttime entertainment for a while.